Apparatus for measuring capacity of a refrigerating machine



Au '.23,1932. J K TY 1,873,127

APPARATUS FOR MEASURING CAPACITY OF A REF RIGERATING MACHINE Filed Nov. 9, 1928 awumtozl Patented Aug. 23, 1932 HABUHISA INOKUTY, OF TOKYO, JAPAN APPARATUS FOR MEASURING CAPACITY OF A REFRIGEBATING MACHINE Application filed November 9, 1928 Serial 110. 818,804. 1

This invention relates to an apparatus for M 7 measuring capacity of a refrigerating machine making use of a direct volume meter for liquid in an enclosed passage, comprising a supplying and releasing device for compressed inert gas, a volume measuring tank connected to outlet of the condenser and arranged in an enclosed refrigerant circuit of the refrigerating machine, a liquid reservoir connected to the expansion valve, a valve and pipe connecting the lower part of the former to the latter, and another pipe connecting upper parts of the tank and the reservoir. The object of the invention is to directly measure the volume of refrigerant circulating in an enclosed refrigeration circuit with almost no change oft-he flowing condition of the refrigerant before and after the apparatus with an extremely small loss of energy while without measuring the pressure differences and applying calculation, so that thecapacity of a refrigerating machine can be measured with great accuracy and remark- In the accompanying drawing, Fig. 1 represents in diagrammatic view, how the new apparatus for measuring the capacity of a refrigerating machine embodying my invention is arranged in the refrigerant circuit of a vapour compresslon refrigeratlng machine. Fig. 2 represents a vertical longitudinal sectron, excepting an inert gas reservoir, through i the new apparatus for measurin the capacity of a refrigerating machine. imilar characters of reference indicate corresponding parts throughout the figures and referring now to the same:

1 is a calibrated measuring tank for the liquefied refrigerant, connected at its top to the condenser 16 of a vapour compressor 12, by the pipe 9 and 19, between which is interposed a valve 21 in order to cut off the apparatus for measuring the capacity of refrigeration out of action, and to short-circuit the refrigerant directly from the condenser 16 to the expansion valve 23, situated just in front of the evaporator 25, by the pipe 19 and through a valve 20. The end of the pipe 9 projects a' little into the upper part of the tank 1 and is bent towards the wall of the supply ofsome inert gas under pressure which same leaving a narrow space between them as shown in Figure2, so as to make the liquefied refrigerant coming from the condenser 16 through the pipe 9 flow gently down along the wall of the tank -1. The tank 1 is connected by a pipe 5 and a cock 5 of a fairly large diameter to another tank or receptacle 3 situated directlybelow the tank 1. a

The end of the pipe 5' is also projected into the upper part of the tank 3, and is also bent toward the wall of the same'leaving a narrow space as shown in Fig. 2, for the same purpose of letting-the liquefied refrigerant to flow down gently along the wall of the tank 3. Each tank 1 and 3 is fitted at one side 7 with a vertical glass tube 2 and 4 respectively, having tubular connections 2', 2' and 4, 4 respectively, with each tank 1 and 3. There is another pipe 6 of a smallerdiameter'- in. comparison with the pipes 19, 9, and 5, conheating the upper parts of the tanks 1 and 3. The function of this pipe 6. is to equalize the pressures in the tanks 1 and 3 as will, how-' ever, be explainedmore fully below. 7 is a three-way valve fitted in a pipe 8, one end of which is opening into the upper part ofthe tank 1 and the other end is connected to a reservoir 8 containing some inert gas under a, proper high pressure, or to the source of is not shown. The remaining one way of the three-way valve 7 is open to free atmosphere by a short pipe 8". The function of the valve 7, the pipes 8, 8", and the reservoir 8, is to introduce or to expel a proper amount of some inert gas into or out of the tanks 1 and 3 of the device as will, however, be explained more fully below. A pipe 10 with a valve 22 leads out of the bottom of the tank 3, and connects the tank 3 to the expansion valve 23. The expansion valve 23 is also connected directly to the condenser 16 through the pipe 19 and the valve 20. With these arrangements the apparatus for measuring the capacity of the refrigerating machine shown in Fig. 1 may be entirely cut out of the circuitof the refrigerant by closing valves 21 and 22, when it is not necessary. to measure the capacity; and the liquefied refrigerant is fed directly from the condenser 16 to the expansion valve cog- - through the expansion the compressor '23 through the pipe 19 and by opening the valve 20. The liquefied refrigerant expands valve 23 into the coil 24 placed in the refrigerator, or evaporator 6 25, where any medium, such as brine,water,

or air, is circulated by a pump 33 as shown in broken lines and arrow-head 32 in Fig. 1, entering in at-26 and leaving out at 27, the 'eva orator the direction of the circulation 10 of t e medium to be refrigerated may, however, be reversed if it is desirable. The refrigerant absorbing heat and having cooled the medium will evaporate and. change into vapour, and will be sucked by the action of 12, the suction side of. which is-connected to the outlet of the coil 24: from the refrigerator 25 by a pipe 28 and valves 29 and 30 as shown in Fig. 1. A pressure gauge will indicate the pressure-of the refrig- 20 erant in the evaporator 25. The gaseous 're-.v

frigerant sucked by the compressor 12 is'compressed to a higher pressure and temperaand is delivered out into a deliverypipe tu-re,

13. A pressure gauge-34:3v attached to this 3 'partof the delivery pipe13, and will indicate the delivery pressure which should be suit- .able for thetemperature of cooling water circulating in the condenser 16.: The gaseous" .refrigera'nt at a higher temperatureand pres sureis led through avalve-14 into the coil- 15 situated in'the body ofthe condenser 16, in

which circulates some cooling medium,gen-

erallycooling water, entering the condenser at 17 and leaving the'same at 18, and passes 1t fas shown inbroken lines and. arrowhead 31 in Fig.1; the circulating device of the coolingwater being not'shown; The ref-rigerant is cooled and re-liquefied as in the usual;

way in the condenser 16, and issent out through Dthe-pip'e 19 to thevalve 21, or 20, according to whether it is necessary or not-neeessary to measure the refngeratingcapacity.

- In an actual circuit 0f a vapor compression refrigerating machine, however,"we may have very frequently some inert gas leftin the circuit'due to the imperfection of evacuation before the first charging of the refrigerant into the circuit, or due to --the impurities in the charge of the refrigerant. It is aiwell known fact that the-"non-condensab'le .gasmust be eliminatedjfrom the circuit in order to imthe action of the refrigerating maprove Especially in. a small household rechine.

' frigeratingmachinewith the automati c'tem-. 9 perature controlling device developedrecentor with a pressure pressure of its temperature.

. It .is'e'vide'nt from what has been explained 'above that the vapour pressure of the refrig-' erant is smaller than the condenser pressure prevailing in the tanks 1 and '3. .And it is,

1y, it is necessary to fill the circuit with very 1.

pure refrigerant containing practically no.

foreign non-condensable gas in the circuit.-

And it is well known that the proper pressure of the refrigerant indicated by the "gauge 34 in the delivery side of I 13, 1 4, 15, 19, 20, 21,9, 1, 5, 3, 6, 10, and 22 the circuit comprising in Fig- 1, must be a little higher than the saturation pressure corresponding to the temperature at and to which the cooling water is capable of condensing and cooling the refrigerant,

rdensat'lon and liquefaction of the refrigerant The liquefied refrigerant o positively certain.

coming out from the condenser 16 and flowing intothe tanks 1 and 3 by the pipes 19, 9,

and 5, is generallyin a state of undercooling',

higher than the saturation therefore,'.not POSSlblG' to have the vapour of the 'refrigerentj evolving from the liquid in the tanks land 3, and we will have neither in order to make' the'action of the convapour space'nor' liquid level'iin the tanks. Hereu-pon we have the necessity of. introduc ing a proper amount of inert gas, supplementing'the deficiency in the vapour pressureof the undercooled liquid tofthe amount equal to the pressure in the condenser.

The amount of the inert gas pressure ofthesaturated vapour 'and' the inert gas, being the sum of the partial pres sure of each constituent vapour. and gas, equal to the pressure'of the delivery side of the circuit as indicated by the pressure gauge Theinertgas iskept storedinthe tank 8 i 2 under pressure,.-or maybe. obtained from some source which'is not shown. The inert gas is led through the pipe 8 into the tanks land 3, and pushes down the liquid in the tanks, expelling all the liquid out of the tankl'into the tank 3. As the diameters of the i e 5" and 'thelvalve 5 are made fairly large,

the liquid will not accumulatein the tank 1 flowing down along thewallTof the tank 1' into ,the tank 3 throughthe large pipe 5 and valve 5. The level of the liquefied refrigerant in the tank 3 will remain unchanged which will be seen in the glass tube 4 as indi- 2, if a proper amount of the cated'll' inFi V inert gas is introducedand the state of the to be introduced "must be such that tomake the total -00 I 1 running. of the refrigerating machine is steady.- Nowthe clear space over the liquid in the tanks 1 and 3 is occupied by a mixture vapor, of the refrigerant at gas introduced. Thet-hree way valve 7, the 'pipe8 and the pipe 8" serve 'of the saturated the-temperature of undercooling and a proper amount of lnert to regulate the quantity of theinert gas, r

leasing it by 8"v or charging it by 8', from the reservoir 8.; There is no danger of the inert 7 the pipe of a sma gas being introduced into the other art of the circuit, because the gas is always eld in the measuring apparatus itself seal by liquefied refrigerant between the valves 21 and 22.

5 To measure the capacity of the refrigerating a definite quantity of liqu d refrigerant,

whether the valve 5 is closed or opened, will always flow to the expansion valve 23 through the pipe 10 and the valve 22, and the liquid level in tank 3 will lower from 11' to a 11 as shown in Fig. 2, for the difi'erence of the pressure due to the change of the liquid level in the tank 3 is negligibly small compared with a large drop of pressure existing at the expansion valve 23 of ordinary refrigerating machines. Then the measurement of the flow directly by volume is effected simply by measuring the time of rise of the liquid level in the calibrated tank 1, which will be clearly indicated in the glass tube 2, by means of a. stop watch or chronometer. After the measurement we open the valve 5, then the li uid in the tank 1 drops down into the tan through the pipe 5 and valve 5 of a fairly large diameter in an instant, and the ori 'nal state of liquid level 11 is at once regalned. Thus we can repeat the measurement of volume of flow of the liquefied refrigerant anew.

Now let the circulating amountv of the liquefied refrigerant measured by the apparatus be V cubic meters per hour,then the ca acity of the refrigerating machine R in kiidgramme-calories per hour becomes] R=Va2wm (11 -6 where w is the density of the liquefied refrigerant in kilogrammes per cubic meter and has a known value from the temperature and pressure of it, i is the total heat of the refri erant at the outletof the evaporator in kifogramme-calories per kilogramme, and i is that at the outlet of the condenser or inlet of the evaporator in kilogra nme-cah oriw per kilo mme and both have definite values accor ng to the pressure, temperature and d ess.

Any refrigerant having a large dro of premure at the expansion valves, suc as carbon dioxide, ammonia, meth l chloride,

I or sulphur dioxide, maybe use Briefly, this invention enables to measure the amount of liquefied refrigerant flowing in an enclosed refrigerant passage by a diliquid meter or liquid flow meter of the indirect type such as Venturi meter orifice me-' h determine,

ter, fpitotmeter, weir, etc., whic the owing amount of liquid by such an indirect method as to require calculation using a constant determined by experiment, but.

also can be used for determining coeflicients for these indirect liquid meters, so that it is an industrial invention ca able to measure the capacity of a refrigerating machine with great accuracy and remarkable ease.

I claim as my invention:

An apparatus for measuring capacity of a refrigerating machine placed in the refrigerant circuit of a re rigerating machine between the condenser and the expansion valve, includinga direct volume meter for the liquefied refrigerant, comprising a volume measuring tank connected tothe outlet of said condenser, a reservoir connected to the inlet of said expanslon valve, a source of inert gas under pressure, means connecting said source to said measuring tank for supplying said inert gas to said measuring tank and reservoir at the desired pressure, a valve and pipe connecting the lower part of said measuring tank to said-reservoir, and another pipe connecting upper parts'of said tank and reservoir, substantially as described. I

In testimony HARUHISA INOKUTY.

whereof I aifix my signature.

rect measurement of its volume, and not only 

